linux/net/ipv6/ipcomp6.c
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   1/*
   2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
   3 *
   4 * Copyright (C)2003 USAGI/WIDE Project
   5 *
   6 * Author       Mitsuru KANDA  <mk@linux-ipv6.org>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22/*
  23 * [Memo]
  24 *
  25 * Outbound:
  26 *  The compression of IP datagram MUST be done before AH/ESP processing,
  27 *  fragmentation, and the addition of Hop-by-Hop/Routing header.
  28 *
  29 * Inbound:
  30 *  The decompression of IP datagram MUST be done after the reassembly,
  31 *  AH/ESP processing.
  32 */
  33#include <linux/module.h>
  34#include <net/ip.h>
  35#include <net/xfrm.h>
  36#include <net/ipcomp.h>
  37#include <linux/crypto.h>
  38#include <linux/err.h>
  39#include <linux/pfkeyv2.h>
  40#include <linux/random.h>
  41#include <linux/percpu.h>
  42#include <linux/smp.h>
  43#include <linux/list.h>
  44#include <linux/vmalloc.h>
  45#include <linux/rtnetlink.h>
  46#include <net/icmp.h>
  47#include <net/ipv6.h>
  48#include <net/protocol.h>
  49#include <linux/ipv6.h>
  50#include <linux/icmpv6.h>
  51#include <linux/mutex.h>
  52
  53static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  54                                int type, int code, int offset, __be32 info)
  55{
  56        __be32 spi;
  57        struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
  58        struct ip_comp_hdr *ipcomph =
  59                (struct ip_comp_hdr *)(skb->data + offset);
  60        struct xfrm_state *x;
  61
  62        if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
  63                return;
  64
  65        spi = htonl(ntohs(ipcomph->cpi));
  66        x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
  67        if (!x)
  68                return;
  69
  70        printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI6\n",
  71                        spi, &iph->daddr);
  72        xfrm_state_put(x);
  73}
  74
  75static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
  76{
  77        struct xfrm_state *t = NULL;
  78
  79        t = xfrm_state_alloc(&init_net);
  80        if (!t)
  81                goto out;
  82
  83        t->id.proto = IPPROTO_IPV6;
  84        t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
  85        if (!t->id.spi)
  86                goto error;
  87
  88        memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
  89        memcpy(&t->sel, &x->sel, sizeof(t->sel));
  90        t->props.family = AF_INET6;
  91        t->props.mode = x->props.mode;
  92        memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
  93
  94        if (xfrm_init_state(t))
  95                goto error;
  96
  97        atomic_set(&t->tunnel_users, 1);
  98
  99out:
 100        return t;
 101
 102error:
 103        t->km.state = XFRM_STATE_DEAD;
 104        xfrm_state_put(t);
 105        t = NULL;
 106        goto out;
 107}
 108
 109static int ipcomp6_tunnel_attach(struct xfrm_state *x)
 110{
 111        int err = 0;
 112        struct xfrm_state *t = NULL;
 113        __be32 spi;
 114
 115        spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
 116        if (spi)
 117                t = xfrm_state_lookup(&init_net, (xfrm_address_t *)&x->id.daddr,
 118                                              spi, IPPROTO_IPV6, AF_INET6);
 119        if (!t) {
 120                t = ipcomp6_tunnel_create(x);
 121                if (!t) {
 122                        err = -EINVAL;
 123                        goto out;
 124                }
 125                xfrm_state_insert(t);
 126                xfrm_state_hold(t);
 127        }
 128        x->tunnel = t;
 129        atomic_inc(&t->tunnel_users);
 130
 131out:
 132        return err;
 133}
 134
 135static int ipcomp6_init_state(struct xfrm_state *x)
 136{
 137        int err = -EINVAL;
 138
 139        x->props.header_len = 0;
 140        switch (x->props.mode) {
 141        case XFRM_MODE_TRANSPORT:
 142                break;
 143        case XFRM_MODE_TUNNEL:
 144                x->props.header_len += sizeof(struct ipv6hdr);
 145                break;
 146        default:
 147                goto out;
 148        }
 149
 150        err = ipcomp_init_state(x);
 151        if (err)
 152                goto out;
 153
 154        if (x->props.mode == XFRM_MODE_TUNNEL) {
 155                err = ipcomp6_tunnel_attach(x);
 156                if (err)
 157                        goto error_tunnel;
 158        }
 159
 160        err = 0;
 161out:
 162        return err;
 163error_tunnel:
 164        ipcomp_destroy(x);
 165
 166        goto out;
 167}
 168
 169static const struct xfrm_type ipcomp6_type =
 170{
 171        .description    = "IPCOMP6",
 172        .owner          = THIS_MODULE,
 173        .proto          = IPPROTO_COMP,
 174        .init_state     = ipcomp6_init_state,
 175        .destructor     = ipcomp_destroy,
 176        .input          = ipcomp_input,
 177        .output         = ipcomp_output,
 178        .hdr_offset     = xfrm6_find_1stfragopt,
 179};
 180
 181static struct inet6_protocol ipcomp6_protocol =
 182{
 183        .handler        = xfrm6_rcv,
 184        .err_handler    = ipcomp6_err,
 185        .flags          = INET6_PROTO_NOPOLICY,
 186};
 187
 188static int __init ipcomp6_init(void)
 189{
 190        if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
 191                printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
 192                return -EAGAIN;
 193        }
 194        if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
 195                printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
 196                xfrm_unregister_type(&ipcomp6_type, AF_INET6);
 197                return -EAGAIN;
 198        }
 199        return 0;
 200}
 201
 202static void __exit ipcomp6_fini(void)
 203{
 204        if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
 205                printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
 206        if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
 207                printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
 208}
 209
 210module_init(ipcomp6_init);
 211module_exit(ipcomp6_fini);
 212MODULE_LICENSE("GPL");
 213MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
 214MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
 215
 216MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
 217